Guinea pigs got their names from the loud, high-pitched squealing they make when they are hungry, or when they are scared, or when they want to be held, or for no damn reason at all. It sounds like this: 'Week week week Weeeeek week WEEEEEEEEEEK!!! WEEEEEEEEEEEEEEEEK!!!! Week week week weeeeek' and it just goes on like that until you give it a carrot or some other leftover vegetable to shut it up. This is why guinea pigs are usually fat. They also make a satisfying purr sound when you pet them.

Guinea pigs come in a few varieties, but the most common are smooth-coated and abyssinian. Smooth coated guinea pigs look like overinflatedrats, and have a shiny coat of short hair. Abyssinian guinea pigs are the closest terrestrian relative to the tribble. They are covered with thick long hair that is intensely whorled. I had a solid black one once named Pudge, and it was difficult to tell which end was the front.

Although the squeaking can get annoying, guinea pigs actually make pretty cool pets. They are social creatures, and will learn to enjoy being petted and held, unlike gerbils or hamsters, who seem to only learn how to restrain their terror. The fact that they are pretty cute helps as well. Care for a guinea pig means keeping it in a cage with newspaper or wood chip bedding that should be regularly changed. Food is store-bought GP chow, augmented with leftover greens from the salad you should be eating every night or two.

My sister and I had a male and female guinea pig when we were younger. When the female is in heat, it is a terrible thing to behold. When we kept them in separate cages, Pudge got as close to Amy as he could, and squeaked as loud as we'd ever heard until we gave in and put him in the same cage as her. Then it was Amy's turn to start squeaking at top volume as Pudge had his way with her. His purring was a nice touch as well. Pudge was a black abyssinian, and Amy was a smooth-coated agouti (the natural color of wild cavies; it's a kind of silvery hair). The babies were all sorts of calico colors, but all were abyssinian. They were very cute balls of fluff, and unlike hamsters, Amy never ate one (that we saw).

In informal English usage, "guinea pig" means the subject of an experiment. In current laboratory research on animals, mice and rats are more commonly used rodents than guinea pigs; however, in the past the guinea pig, or cavy, was widely used in scientific research. The biggest boom in their use came in the 1880s after two discoveries in bacteriology: in 1882 German bacteriologist Robert Koch used guinea pigs to discover the bacterium that causes tuberculosis because mice and rats did not develop obvious symptoms, and in 1884 German bacteriologist Friedrich Löffler (or Loeffler) discovered that mice and rats were not very susceptible to diphtheria, but guinea pigs are extremely sensitive to it. In fact, guinea pigs have an immune system much more like that of humans than most rodents, and so were the most widely used test animal in the tracking down of disease germs in the late 1800s and early 1900s.

Guinea pigs are also one of the few lab animals which require vitamin C in their diets rather than being able to synthesize it in their bodies; this led to the discovery of vitamin C in 1907. They are still used to study body processes which require vitamin C. They also need to take in folic acid, thiamine, arginine and potassium, making them useful in other nutrition studies. NetVet Veterinary resources cites some additional features which make guinea pigs useful in research:

Overall, guinea pigs have contributed to 23 Nobel Prizes in medicine or physiology. Guinea pig studies led to the discovery of the hormoneadrenaline and helped develop replacement heart valves, blood transfusions, antibiotics and asthma medicines, as well as vaccines for diptheria and tuberculosis. Given these past achievements, it is somewhat surprising that they now seem to make up a very small percentage of laboratory experimental animals, between 1% and 2% depending on which source is used. This decrease seems to stem from new allergy tests for skin sensitivity and other things which formerly used guinea pigs and now use mice, or no longer use animals. And of course, this animal is not like humans in every way; Howard W. Florey, who worked with Alexander Fleming in refining pencillin, said in a speech in 1953:

Mice were used in the initial toxicity tests because of their small size, which economised the precious material, but what a lucky chance it was, for in this respect man is like the mouse and not the guinea pig. If we had used guinea pigs exclusively, we should have said that penicillin was toxic...This perhaps carries with it the suggestion that the dramatisers of science who wrote for the public press might with some appropriateness refer to "human mice" rather than to "human guinea pigs" in the future.

The Oxford English Dictionary notes the first written use of "guinea pig" in its generic test-subject sense in 1913 (by George Bernard Shaw). It became widely known enough that in 1933 consumer researchers F. J. Schlink and Arthur Kallet wrote a book called 100,000,000 Guinea Pigs, and by 1953 Dr. Florey gave the above comment on the inaccuracy of the usage. By 1970 even a Czech author, Ludvík Vaculík, titled an anti-Communist book The Guinea Pigs (Morčata in Czech), showing that the usage is not limited to the English-speaking world.

So I buried my guinea pig yesterday. I took it pretty hard, relatively - that is to say I was the only one in my family who shed tears over our diminutive departed critter. At first, I was just like the rest of my family members, making a few comments about "life" or "it happens," filling the gaps with a few sighs. But then the memories welled up: his tiny, warm weight on my chest as I lay supine, his inquisitive nose checking me for the millionth time as if I were unfamiliar. He would then perch immutably there, claws and paws clutching my t-shirt, always somehow ambiguous between the two extremes of petrifaction and relaxation (this is the default state of a guinea pig). It was only then, picturing this, that I started to cry.

I always seem to be the only one thinking this: when somebody dies, thoughts and prayers always for the surviving family members seem to outnumber thoughts for the deceased person. What's it like to be him right now? The dead guy. He must have found out by now whether or not there's an afterlife. And you have to wonder how he's taking it.

Only being sad about about our lost times together is was a revelation of what pet relationships truly are. I was most sad when I realized that a source of joy for me had gone away forever; I didn't sob upon seeing and processing little Furball's still body and mind for the first time. I insist: grieving for pets is, essentially, a selfish activity. Instead of thinking of the wasted potential on guinea's end, I thought about mine and erroneously labeled it "ours." I worry that there is a danger of seeing human beings like I saw my lost pet- as mere sources of laughter and stimulation, the other party in a two-man contract (or worse, one-way contract) to amuse ourselves and kill time. A modern notion, of course. If you find that friend time competes directly with TV time, this is a problem. When I die, I want my eulogy to be more than "We had some good times with this kid" and "Darn, we could have had more." I want my eulogy to be honest. I wanna be classified human. I wanna be irreplaceable...if possible. If people weep only selfishly, I've done it wrong. I was fun to be around, sure, but true connection was always missing. I want to be connected!